Definitions looking for words

Wanting to scratch your bum while walking down the street but not being able to because somebody is walking right behind you - this word for this one is 'tinea'.

The habit of walking around the house and performing tasks while singing small snatches of nonsensical song out of habit - this one, I believe, is 'Tourette's'.

Waking up with an itchy finger, scratching it, but then finding that it is still itchy, and stays itchy for the next half hour or so - I'm afraid this one is 'leprosy'.

Aren't words wonderful!